Dryer failure solution - Huaqiang Electronic Network

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Although the drying of plastic granules is a relatively simple process, in some cases the granules cannot be completely dried. The factors that affect the drying effect are:

1,

In the dryer, the moist air is first removed to contain a very low residual moisture. Then, by heating the air to reduce its relative humidity. At this time, the dry air has a low vapor pressure. By heating, the water molecules inside the particles are free from the binding force and diffuse to the air around the particles.

Pay particular attention to air filters and hoses when inspecting the dryer. A blocked filter or a flattened hose will reduce the airflow and affect the operation of the dryer; the damaged filter will contaminate the desiccant and inhibit its ability to absorb moisture;

2. Heat is the key to the joint force between the open water molecules and the hygroscopic polymer. When it is above a certain temperature, the gravitational force between the water molecules and the polymer chain is greatly reduced, and the water vapor is carried away by the dry air.

In the dry gas path, the drying temperature should be checked at the inlet of the silo to compensate for the heat loss of the dryer in the hose. The low air temperature at the entrance to the silo may be due to improper regulation of the controller and lack of insulation, or failure of the heater element, heater contactor, thermocouple or controller.

3. In the air around the particles, the absorption of heat and the diffusion of water molecules to the surface of the particles take a certain amount of time. Therefore, the resin supplier should specify the time it takes for a material to dry effectively at the proper temperature and dew point.

4. The dry hot air transfers the heat to the particles in the dry silo, removes moisture from the surface of the particles, and returns the moisture to the dryer. Therefore, there must be sufficient gas flow to heat the resin to the drying temperature and maintain this temperature for a certain period of time.

After the material has not been properly dried from the dryer, the dry silo should be checked for sufficient space to provide adequate and effective drying time. Effective drying time refers to the time during which the particles are actually exposed to the proper drying temperature and dew point. If the residence time of the granules in the silo is insufficient, proper drying is not obtained. Therefore, attention should be paid to the size and shape of the pellets or the crushed materials, which affect the bulk density and residence time of the dried materials.